Experimental Investigation of Gas Dynamic Effects Using Nanoporous Synthetic Materials as Tight Rock Analogues

Transport in Porous Media - To improve the understanding of gas transport processes in tight rocks (e.g., shales), systematic flow tests with different gases were conducted on artificial micro- to...     

'Genetics home reference': helping patients understand the role of genetics in health and disease

The surge of information generated by the Human Genome Project has left many health professionals and their patients struggling to understand the role of genetics in health and disease. To aid the lay public and health professionals, the US National Library of Medicine developed an online resource called 'Genetics Home Reference' (GHR), located at http://ghr.nlm.nih.gov/. Launched in April 2003, GHR's goal is to help the public interpret the health implications of the Human Genome Project. It bridges the clinical questions of consumers and the rich technical data emerging from the sequenced human genome. The GHR web site is designed for easy navigation among summaries for genetic conditions and the related gene(s) and chromosome(s). This design strategy enhances the user's appreciation of how genes, chromosomes, and conditions are interrelated.     

Macrocyclic thioether design by molecular modelling

Abstract

Two trithiamacrocycles have been designed by molecular modelling to have preorganised endodentate sulfur donor atoms. These new macrocycles have five- and six-membered saturated heterocycles inserted into 2,5,8-trithia[9]-m-benzenophane; molecular dynamics simulations suggest that the endo forms will be rigid on a nanosecond timescale. Optimum metal-sulfur distances which the new ligands will accommodate lie between 2.76 Å and 2.95 Å, suggesting they will be particularly suitable for a large soft metal ion such as silver(I).     

Unusual Acetylation‐Dependent Reaction Cascade in the Biosynthesis of the Pyrroloindole Drug Physostigmine

Physostigmine is a parasympathomimetic drug used to treat a variety of neurological disorders, including Alzheimer’s disease and glaucoma. Because of its potent biological activity and unique pyrroloindole skeleton, physostigmine has been the target of many organic syntheses. However, the biosynthesis of physostigmine has been relatively understudied. In this study, we identified a biosynthetic gene cluster for physostigmine by genome mining. The 8.5 kb gene cluster encodes eight proteins (PsmA–H), seven of which are required for the synthesis of physostigmine from 5‐hydroxytryptophan, as shown by in vitro total reconstitution. Further genetic and enzymatic studies enabled us to delineate the biosynthetic pathway for physostigmine. The pathway features an unusual reaction cascade consisting of highly coordinated methylation and acetylation/deacetylation reactions.     

Stimuli‐Responsive Theragrippers for Chemomechanical Controlled Release

We report on a therapeutic approach using thermo‐responsive multi‐fingered drug eluting devices. These therapeutic grippers referred to as theragrippers are shaped using photolithographic patterning and are composed of rigid poly(propylene fumarate) segments and stimuli‐responsive poly(N‐isopropylacrylamide‐co‐acrylic acid) hinges. They close above 32 °C allowing them to spontaneously grip onto tissue when introduced from a cold state into the body. Due to porosity in the grippers, theragrippers could also be loaded with fluorescent dyes and commercial drugs such as mesalamine and doxorubicin, which eluted from the grippers for up to seven days with first order release kinetics. In an in vitro model, theragrippers enhanced delivery of doxorubicin as compared to a control patch. We also released theragrippers into a live pig and visualized release of dye in the stomach. The design of such tissue gripping drug delivery devices offers an effective strategy for sustained release of drugs with immediate applicability in the gastrointestinal tract.     

A radioanalytical phantom for assessing the efficacy of electrokinetic decontamination of entrained radioactivity within concrete media

A phantom for the evaluation of electrokinetic remediation of radioactive species from water saturated concrete is described. The phantom has been designed to be a general analogue for environments where structural concrete is saturated by radioactive aqueous solutions and where electrokinetic remediation may be deployed. It is also a specific analogue for the walls of storage ponds for legacy spend nuclear fuel pins where the pond water comprises a large volume of hazardous active waste that may penetrate the pond wall. The fabricated phantom was evaluated using a fixed electrical potential to monitor the rate of cationic transport of K⁺ through concrete samples of different thickness (20 and 35 mm respectively). Results of the evaluation show K⁺ diffusion coefficients of 5.20 × 10^?13 and 7.61 × 10^?13 m² s^?1 for the 20 mm and 35 mm samples, consistent with those seen in literature for the transport of caesium through concrete of similar thickness. The phantom offers a means of experimental validation of computational electrokinetic models as well as providing a basis to test the effects of electrode material on ionic transport rates, to interrogate the effects of pH on all components of the system, and as a basis for instruction, education and training in nuclear decommissioning and waste treatment.     

On the complexity of a bundle pricing problem

We consider the problem of pricing items in order to maximize the revenue obtainable from a set of single minded customers. We relate the tractability of the problem to structural properties of customers’ valuations: the problem admits an efficient approximation algorithm, parameterized along the inhomogeneity of the valuations.